AMMONIA REMOVAL DURING BIOFILTRATION AS AFFECTED BY INLET AIR TEMPERATURE AND MEDIA MOISTURE CONTENT

Biofiltration is a promising technology for minimizing odor and gas emissions from livestock buildings. A laboratory experiment investigated N accumulation and N transformations to better understand how biofilters remove airborne NH3. Total-N accumulated in the media accounted for only 29% of the N removed by the biofilter after 1160 h. The fate of the remaining N is unknown. Nitric oxide (NO) gas emission accounts for only a small part (<2%) of the difference, and no N was lost via leaching. Microsite denitrification to dinitrogen (N2), nitrogen dioxide (NO2), or nitrous oxide (N2O) may explain some of the discrepancy, but further research is needed. An attempt to determine N transformation rates was not successful due to continuous modeled circular N transformations. Despite these unexplained N fates, this experiment showed that biofiltration can effectively remove NH3 levels from exhaust air.